Apparatus for bleaching



xx 3,42m554 I APPARATUS FOR BLEACHING Filed March 12, 1965 Sheet INVENTOR ,4 Lys S/MONS ATT RNEY Feb. 11, 1969 1 o 3,426,554

APPARATUS FOR BLEACHING Filed March 12. 1965 Sheet 3 of 2 INVENTOR ALoys SIM IS ATTORNEY United States Patent K 52,366 US. (:1. 68-9 Int. Cl. D06c 1/10; D061 3/08 7 Claims The applicant claims the benefit of German application Ser. No. K 52,366, filed Mar. 13, 1964.

It is known to treat fabric or vegetable materials with gaseous C10 or with an aqueous solution of C10 According to the known process, the fabric is washed in the usual way and is then disposed in a water-filled receptacle. Thereupon, C10 is conducted into the water in the receptacle to the amount of 60 to 80 g. to 1 kg. of goods. The water thus enriched with C10 is then heated moderately, and the fabric is subjected for several hours, under frequent agitation, to the action of the aqueous solution (DPS 413.228).

Working in a similar manner with gaseous C10 which is conducted into one of the fabric-containing gastight chambers, then one would likewise need a lengthy action of the gaseous C10 for bleaching, as the C10 concentration in the gaseous mixture constantly takes off.

In contrast to such a non-continuous bleaching process with gaseous ClO or an aqueous solution of C10 the invention has for its object a continuous process for bleaching fabrics or yarns.

The bleaching of fabric in continuous process is known of itself. According to that process, fabric to be bleached is first treated with an alkaline solution, and then, soaked in a Weaker alkaline solution, is treated with gaseous chlorine. After removal of a part of the absorbed chlorine, the fabric is conducted into a warm alkaline bath, and thereafter-should it be necessary, after an intermediate rinsing and a second impregnation with an alkaline solutionthe material which has been wetted with the alkaline reagent is again treated with gaseous chlorine and undergoes an additional chlorination.

Finally, the fabric is once more given a short treatment with an alkaline solution, whereby hypochlorite is formed, so that a higher degree of whiteness is attained. In this process the fabric which is impregnated with the alkaline solution is drawn through a chamber with chlorine gas, in which it is exposed to the action of the chlorine gas (DPS 813.024).

Other continuous bleaching processes set forth the impregnation of the fabric with a suitable chemical solution and exposing it in a warm and moist atmosphere to the action of a suitable liquid, such, for example, as a reaction medium, a catalyzer, a heat carrier, or the like, while that is slung against the surface of the products to be handled in the form of concentrated and recovered single jets, whose penetrating strength is so great that the desired effect immediately appears in the depth as well as on the surface of the goods (DPS 808.825).

In this process, the fabric carriage must be drenched with a bleaching medium which has first received its bleaching effect through a catalyzer.

In contrast to such a bleaching process with fluid bleaching mediums, the invention has for an object a rapid bleaching of textile materials in a continuous process with a gaseous bleaching medium. According to the process of the invention, air-dry or dampened fabric web materials are conducted in extended condition through treatment chambers and beaten with circulating whirling gas from blowers, in particular, air currents to which flowing C10 gas is admixed. Because of this flowing admixture, the degree of concentration actually desired 3,426,554 Patented Feb. 11, 1969 ice is maintained during the treatment. Moreover, the C10 air mixture, because of the blowing from the blowers, is brought into intensive contact with the goods carriage, forcing itself into the heart of the same.

If the goods are not already wet when they arrive from the foregoing simple treatment, then it is recommended that the goods t-rain be moistened lbefore entrance into the treatment chamber, for example, with water to which has been added a standard acid moistening medium and a buffer salt, but, in order to achieve a possibly lasting concentration of C10 in the moisture content of the goods with a small C10 concentration in the air, too high a degree of wetness should not be selected. The rapid leveling off of the concentration in the moisture brought about by the blowing up in the ClO -air mixture out of the blowers provides for a uniform bleaching effect throughout the entire material carriage cross-section.

The percentage of C10 in the circulating air current is thereby held considerably under the explosion danger safety limit, which, at room temperature, lies somewhat above 10% by volume. In the use of higher temperatures, it is necessary to operate with a correspondingly low percentage. On the other hand, it is advantageous to operate at higher temperatures, for example to about 50 C., as the rapidity of the bleaching effect of the C10 increases with the rise in temperature.

To keep up the C10 content, percentagewise, in the circulating whirling air current, a part of the air current is conducted over generator for Clo -gas and, after enrichment with C10 is again led to the treatment chamber.

The production of C10 in the generator or developer is adapted to suit the consumption by adjustment of the pressure control prevailing in the developer, which controls the feeding in of the outgoing chemicals.

The material may be dried at a low moisture content at the same time that it passes through the bleaching layout. In this case, the moistening means must contain so much lye that, during the drying, the pH value in the moisture residue does not fall below an amount which could lead to damage to the material. The material dried out thus far may be stored in one of the airing chambers annexed to the bleaching layout.

However, for the purpose in view, the material, during its prograss through the bleaching layout, will be held to its moisture content while saturated or nearly saturated air is whirled about. If necessary, the moisture-content desired at any given moment may be attained through the blowing of steam into the bleaching chamber. After leaving the bleaching chamber, the material may be conducted through a washing apparatus with squeezers for neutralization and removal of chlorates and following that through an annexed drying chamber for drying.

For the purpose of carrying out the bleaching process for material with gaseous C10 according to the invention, a layout is employed which, besides a moistening apparatus, possesses a closed treatment chamber in which an air take-off creates a constant pressure control, and a part of the circulating, whirled-about air is sucked back through one of the conduits attached to the treatment chamber and leading to the developer and cause to flow over the surface of the liquid in the generator, and, after enrichment with C10 is again led back to the sucking end of this or that air whirler. To maintain a small pressure control from the ventilator, the sucked-off air flows through a washing tower, in which the C10 is washed out before the exhaust air enters the open air. The wash water, with small C10 content, can be used as moistening water for the incoming goods. In this case, the moistening apparatus will be drawn along into the pressure control area.

In the drawing, a layout for carrying out the bleaching process for textile material according to the invention is schematically set forth.

FIG. 1 shows a perpendicular lengthwise section an FIG. 2 a horizontal section on the line 11-11 of FIG. 1 through a bleaching layout.

The material 1 is led in over a moistening apparatus 2 with connected squeezing rollers 3 for the adjustment of the moisture and thereafter over guide rollers 4 into a treatment chamber 5 consisting of two sections set to gether.

In the treatment chamber 5, the carriage is carried forward alternately, in zigzag fashion, over upper driven rollers 6 and lower free-running conducting rollers 7. The treatment chamber may also be constructed of more than two sections. A larger stock of goods may be taken up at one time over the extended length of a plurality of superimposed treatment sections and added to the other goods in the last section and treated with a current of gas consisting of practically exhausted Clo -gas. The sections are divided from one another by partitions. Through a ventilator 9 at the end of the treatment chamber exhaust gases practically completely free of C10 are led off. The ventilator 9 is so constructed that a constant pressure control prevails in all sections, whereby a going out of ClO enriched gas in the work room is prevented. For the continual liberation 01": C10 these exhaust gases may flow through a wash tower 26, the water of which, suitably enriched with the C10 residue of the exhaust gases, is led back to the moistening apparatus. In such case, the moistening apparatus will be included with a vent in the developer 21 for the feeding of the pressure control pro= duced by the outgoing goods.

Between the individual goods carriage loops, blowers 10, 11 project alternately from below and above, and are attached to lead-in canals 12, 13. The canals 12, 13 are fed with whirling air currents 14, 15. These again suck in the gas mixture which, for the most part, has been sucked off from the blowers 10, 11, after the unrolling of the goods 5, for a renewed unrolling. To maintain the concentration, the Cl0 enriched gas mixture is constantly led into the whirling air currents 14, 15, through conduits 1-6, 17, 18. For that purpose, a branch current of the gas current whirled around in the last section of the treatment chamber is sucked out of the return canal 28 (FIG. 2) into the whirling air 22, 23, by a conductor 19 from a vent 20 over the surface of the developer liquid in a C10 developer 21, and thereby is enriched with the ClO produced in the developer 21. Instead of leading the entire branch current over the surface of the developer liquid, a smaller portion may be sucked through the developer liquid drop by drop, in order to carry along the self-build ing C10 in the reaction solution and carry it off.

Through the ingress and egress slits 24, 25, of the goods carriage 1, the part of the exhaust led oif into the open air through the ventilator 9 is replaced with fresh air.

Through the dividing up of the layout into a plurality of sections, it is possible to treat the goods carriage 1 in the superimposed sections with a gas mixture of constantly decreasing Cl0 concentration and to use up prac= tically constantly the C10 content, so that losses of C10 in the exhaust are very small.

It may be recommended to provide a heat register in the return-conductor 28 of the gas mixture, in order to strengthen the bleaching etfect of the C10 In view of the danger of explosion with increase in temperature, it is advantageous to work with higher tempera tures in the superimposed sections, so that the danger of explosion will decrease when the C10 content lowers.

In the preferred procedure the moisture content of the fabric 1, when treated with the whirling currents or jets should be in excess of 20% and the percentage of chlorine dioxide in the whirling air currents should be between 0.5 to 7% by volume and the goods may be moistened with dilute lye or caustic alkali. The partitions on both sides of the fabric in the chamber between the guide rollers will direct the blasts onto both sides of the fabric.

I claim:

1. An apparatus for bleaching an extended textile web with whirling currents and jets of air containing chlorine dioxide comprising an elongated closed treatment chamber having an inlet side and an outlet side and top and bottom walls, the inlet side having an inlet slot for the extended web at one end and the outlet side having an outlet slot for the web at the other end, a carrier arrangement for conducting the extended web in sinuous zig-zag fashion extending from adjacent the top wall to adjacent the bottom wall from the inlet side to the outlet side, generators positioned along the walls of the elongated vessel for generating whirling currents and jets of air containing chlorine dioxide, directing means from directing said currents forcibly upon both sides of the extended web, an exhaust system for removing the air containing residual chlorine dioxide from the chamber, a washer for washing said removed air with wash water to remove chlorine dioxide, a closed vessel through which the web passes before passing through the inlet slot serving as a moistener containing means to moisten the fabric entering the treatment chamber, a return line from the washer to conduct wash water containing removed chlorine dioxide to the moistener to provide in said moistener wash water to moisten the fabric passing therethrough, a producer having a liquid body to generate chlorine dioxide, a gaseous conduit to conduct air containing chlorine dioxide from within the treatment chamber to the producer to enrich the air with additional chlorine dioxide and additional gaseous conduits to conduct the enriched air from the producer to the generators.

2. The apparatus of claim 1, said return line being connected to opposite sides of the treatment chamber adjacent the outlet side and extending along each side of the chamber toward the inlet side.

3. The apparatus of claim 1, conduits between the directing means positioned alongside the sides of the treatment chamber.

4. The apparatus of claim 1, said moistener having a series of rollers, first to moisten the fabric and then to squeeze out the excess moisture from the fabric.

5. The apparatus of claim 1, in which air current generators are positioned at the opposite corners of the chamber for creating said whirling currents of air.

6. The apparatus of claim 1, in which two chambers are placed in series and succession, each provided with blowers at opposite corners thereof serving as said generators for creating whirling currents of air.

7. The apparatus of claim 1, said directing means having partitions extending along both sides of the fabric for directing upon both sides of the fabric whirling blasts of air containing 0.5 to 7% by volume of chlorine dioxide gas.

References Cited UNITED STATES PATENTS 2,199,233 4/ 1940 Williams 8149.1 X 1,580,136 4/ 1926 Hamburger et al 8108 3,291,559 12/1966 Robson et al 8108 FOREIGN PATENTS 337,305 10/ 1930 Great Britain.

MAYER WEINBLATT, Primary Examiner.

US. Cl. X.R. 

7. THE APPARATUS OF CLAIM 1, SAID DIRECTING MEANS HAVING PARTITIONS EXTENDING ALONG BOTH SIDES OF THE FABRIC FOR DIRECTING UPON BOTH SIDES OF THE FABRIC WHIRLING BLASTS OF AIR CONTAINING 0.5 TO 7% BY VOLUME OF CHLORINE DIOXIDE GAS. 